The present invention relates to an active orthopedic appliance for aiding in the correction of Class III malocclusions and malocclusions with underdeveloped maxillas and, more particularly, to an improvement to conventional orthopedic correctors employed by orthodontists to correct Class III type malocclusions. A Class III malocclusion is defined as a malposition of the maxillary and mandibular teeth and denture bases so that the lower arch is anterior to the upper arch, resulting in an esthetically unattractive face. An underdeveloped maxilla is a maxilla that is deficient anterioposteriorly, thereby giving the face and teeth a Class III appearance. The characteristics of this type of malocclusion are a long mandibular body, frequently underdeveloped maxilla, and maxillary incisors occluding lingually to the mandibular incisors or a combination thereof.
The basic objectives of treatment for a Class III malocclusion or underdeveloped maxilla are:
1. Eliminate the forced bite; PA1 2. Retard excessive mandibular growth horiziontally; and PA1 3. Stimulate all possible anterior-posterior development of the maxilla, if it is underdeveloped.
If there is maxillary underdevelopment, the use of a functional, removable active orthopedic appliance has proven to be efficient in restoring normal arch form and size through the medium of expansion. The general philosophy of treatment is to eliminate all restricting influences on the maxilla and thereby obtain the greatest possible potential of the normal growth and development pattern. The use of fixed appliances, such as braces and chin caps with extra oral force to exert a retruding pressure on the mandible, has proven effective and may be used in conjunction with a functional, removable active orthopedic appliance in the treatment of a Class III malocclusion.
During treatment of certain Class III type malocclusion cases with an orthopedic appliance, the crowns of the premaxillary teeth are moved anteriorly. However, due to the nature of the orthopedic appliance and the pressure of the lips on the gingiva and the alveolar process, the roots of the premaxillary teeth remain unmoved. This results in an inclination of the premaxillary teeth which is not cosmetically pleasing and which often results in a relapse of the premaxillary teeth to their original position.
The present invention uses a segmented bow with acrylic pads affixed to the ends of each of two segments to reduce the lip pressure and thereby allow a translatory movement of the maxillary teeth and alveolar process. The segmented bows may be attached to the sides of the active orthopedic appliance with solder or suspended on a wire originating in the acrylic portion of the appliance. The two segments are extended from their points of attachment around the perimeter of the gum of the premaxillary segment. The bow is segmented or split. In other words, the bow is not continuous from point of attachment on one side of the appliance around the perimeter of the gums to the point of attachment on the other side of the appliance. The purpose of the split bow as opposed to a continuous bow is to allow more flexing movements of the bow, thereby alleviating pain and irritation to the patient. Prior to the use of the segmented labial archwire with acrylic pads of the present invention, it was common to initiate orthognathic surgery to move bone and premaxillary teeth forward. It has been found that patient cooperation with the use of the present invention is excellent, partially due to the fact that it is painless. An orthodontist is especially concerned with the level of patient cooperation because the patient is actively involved in the treatment through the required care and activation of the appliance and the frequency and duration of wearing the appliance. Any pain experienced by a patient expectedly results in less frequent use of the appliance and lesser duration of use.
The appliance of the present invention may also be outfitted with various orthodontic attachments, such as lingual archwires or springs, to induce the movement of individual teeth.